C Programming that calculate the area of a circle

#include <stdio.h>
#include <stdlib.h>

int main()
{
    float r,area;
    printf("\n\t enter the area of a circle= ");
    scanf("%f",&r);
    area=3.14*r*r;
    printf("\n\t the area of a circle is = %.2f",area);
    return 0;
}

  the output

enter the area of a circle= 3

 the area of a circle is = 28.26